This disclosure relates to a linear bearing. In a linear motion bearing, a generally cylindrical housing is designed to move relative to a shaft. The housing includes a ball retaining structure comprising a plurality of ball retaining elements. Each ball retaining element includes a plurality of ball bearings moveable in a track. The elements are mounted within the housing so that movement of the housing with respect to the shaft is effectuated through engagement of the bearings with the shaft. As the housing moves, the ball bearings move in respective tracks.
Prior art systems included ball retainer structures that needed to be individually assembled and carefully fitted into an outer assembly. Each component, including all of the ball bearings were loose elements that required time-consuming and expensive manufacturing processes. Should one retainer structure become loose, all of the ball bearings would disassemble and require a complete reassembly.
FIGS. 1 and 2 illustrate a prior art linear motion bearing assembly 40. The bearing assembly includes ball retainer element 42, load bearing plates 44, ball bearings 46, ball retainer segments 54, outer housing sleeves 48, 50 and bearing plate to housing intermediary load structure 52. In prior art bearing assembly 40, the ball retainer structure 42 included a plurality of ball retainer segments 54, each operatively associated with an adjacent ball retainer segments along longitudinal sides thereof to form a ball retainer structure having a bore there through for receiving a shaft. Each ball retainer segment 54 included an outer radial surface 56 and an inner radial surface 58. Axial ball tracks 60 were formed in the outer radial surface 56 of each ball retainer segment 54 and include load bearing portions 62, return portions 64 and turnarounds 66. A longitudinal bore 68 in the inner radial surface 58 of the ball retainer segment 54 extends substantially the length of the load bearing portions 62 and accesses support shaft 70.
A plurality of ball bearings 46 were disposed in the ball tracks 60 with those ball bearings 46 in the load bearing tracks 62 extending at least partially into longitudinal bores 68 to contact support shaft 70. A locking structure in the form of locking clips 72 were formed on opposing longitudinal ends of each ball retainer segment 54 to facilitate assembly with outer housing sleeves 48, 50.
To assemble the bearing assembly shown in FIG. 1, the ball bearings 46 needed to be placed within a ball retainer segment 54. A load bearing plate 44 was then placed upon the ball bearings 46. This structure was then carefully inserted into a sleeve 48, 50, which applied pressure onto load bearing plate 44 to maintain ball bearings 46 in ball retainer segment 54. Each structure needed to be carefully assembled and inserted into the sleeve 48, 50. Should one structure move during assembly, the ball bearings 46 often spilled out of the structure, thus having to be completely removed and reassembled. This assembly process was both time-consuming and expensive. In addition, this structure required all of the components shown in FIG. 1 to operate properly.
The present disclosure describes improvements on these prior art systems.